I suspect there is also an issue with soil depletion if you were to harvest wood at the level you are talking about. One must be careful to not do what you suggest above (e.g. when you write “any woody plant material will do”). For a better example of what to do, in the Woodburner’s Encyclopedia (a 1942 book!), Jay W Shelton writes,

Does the tipping point introduce an Ice Age?

If so how long do we have to buy some artic gear to ensure our survival ?

Maybe that can slow down our consumption.

I’m not in the half full category at present.

“Although the melting of underlying permafrost will release huge amounts of the greenhouse gases blamed for fuelling global warming, researchers who sampled three sites in boreal Alberta, Saskatchewan and Manitoba have discovered that the warmer, softer, wetter soil that results also promotes the growth of new mosses that capture and store about as much carbon from the atmosphere as the thawed ground releases.”

http://www.nationalpost.com/ news/ story.html?id=48927d0f-43eb-4f11-8426-a689c9d45960&k=46303

http://www.treehugger.com/ files/ 2007/ 08/ peat_moss_may_s_1.php

http://www3.interscience.wiley.com/ journal/ 117991633/ abstract?CRETRY=1&SRETRY=0

Yes, we have committed to have an excursion.
Yes, it will be very, very inconvenient.
No, Earth’s climate is not going to run away.

I at first thought I was seeing a headline from The Onion
“Runaway Climate Captured?”

But alas, it’s a different kind of joke — it’s a Milloy:
http://www.foxnews.com/story/0,2933,295361,00.html

This is why ‘runaway’ is just the wrong word.

Lightning, lightning bug. You know your Twain.

I wish you’d retitle this. Say “dangerous” or “disastrous” or “egregiously inconvenient” or “goddamm ugly” but not “runaway.”

Runaway means won’t come back.
It’s the wrong word if you try to keep to the scientific sources.

We’re talking about an excursion.
An excursion in hell, yes.
For several human lifetimes, yes.
But not a runaway. Not to Mars-like, and not to Venus-like, endpoints.
It’s an excursion, dammit.
Earth abides.

Q.v.:

RC:
[Response: We are a long way from any ‘runaway‘ effects, and yes, the planet (as a whole) will recover, though the timescales to fully remove all the excess carbon we are injecting are longer than you or I are likely to care about. -gavin]
— 2 October 2007 http://www.realclimate.org/?comments_popup=475

http://www.realclimate.org/index.php?p=272
5 July 2006 Runaway tipping points of no return
Gavin’s several-paragraph introduction there sums it up well.

“… People often conclude that the existence of positive feedbacks must imply ‘runaway’ effects …. You can think of the Earth’s climate (unlike Venus’) as having an ‘r’ less than one, i.e. no ‘runaway’ effects ….”

Yes, some people use “runaway” for anything beyond inconvenience in their own immediate future. But look who they are — mostly people who are “skeptics” trying to make the problem look exaggerated so they can then shrug it off.

from

http://en.wikipedia.org/wiki/Biochar

and like torrefied wood is a superior fuel compared to fossil coal.